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The antibacterial activity against Staphylococcus aureus of aerogels fabricated from colloidal suspensions of chitosan/chondroitin sulfate nanocomplexes is analyzed. Upon freeze-drying the colloidal suspensions, the aerogels presented a porous structure made of microsheets and microfibers. The aerogels could, in addition, be loaded with antimicrobial agents. Loaded with the antibiotic erythromycin, the aerogels showed crystalline deposits, affecting the topography of the samples as well as their mechanical properties, showing a decrease on the apparent Young's modulus and hardness at 40% deformation. Loaded with elephant garlic (Allium ampeloprasum L. var. ampeloprasum) extract, the aerogels showed texturization of the microsheets and microfibers, and the higher relative mass allowed an increase on the apparent Young's modulus and hardness at 40% deformation with respect to pristine aerogels. Unloaded aerogels showed activity against Staphylococcus aureus, including a methicillin-resistant strain. The release of erythromycin from the aerogels to an agar environment is governed by equilibrium forces with the polysaccharides, which allow modulating the load of antibiotic and its concomitant diffusion from the material. The diffusion of the active components of the elephant garlic extract did not show a dependence on the polysaccharide content, revealing a week interaction. The elephant garlic extract resulted active against the methicillin-resistant Staphylococcus aureus strain, while resistance was found for the antibiotic, revealing the therapeutic potential of the natural extract. The antimicrobial aerogels may be used for several therapeutic purposes, such as healing of infected chronic wounds. [ABSTRACT FROM AUTHOR]

Abstract: The importance of the linear aromatic density of polyelectrolytes on the ability to bind and influence the state of aggregation of dyes such as rhodamine 6G is highlighted. The corresponding complexes present different interaction patterns with metal ions such as Cu2+, undergoing different spectroscopic changes. The chemical bases of these changes are discussed. The different polyelectrolytes studied, poly(sodium 4-styrenesulfonate), poly(sodium 4-styrenesulfonate-co-sodium maleate) at two different comonomer compositions (3:1 and 1:1), and poly(sodium acrylate-co-sodium maleate), bear different linear aromatic density and induce different R6G binding patterns, as seen by diafiltration and UV–vis spectroscopy of absorbance and fluorescence. As the linear aromatic density increases, smaller dye aggregates are induced in the systems. Thus, in the presence of a large excess of the polyelectrolyte showing the highest linear aromatic density, the dyes disperse on the polymer domain and no aggregation is detected. The interaction is less sensitive to the cleaving effect produced by the addition of NaCl 0.1M for the complexes that include the polyelectrolytes with the highest linear aromatic density. In the presence of Cu2+, the complexes formed with the polyelectrolytes showing the lowest linear aromatic density tend to cleave, producing the release of the dye from the polymer domain. On the contrary, the complexes formed with the polyelectrolytes showing the highest linear aromatic density effectively retain the dye in the presence of the divalent metal ion. Based on fluorescence changes by the addition of different amounts of Cu2+ to the solution, the potential of the polyelectrolyte/R6G complexes in applications as sensing materials is discussed. [Copyright &y& Elsevier]

The incidence of ulcers associated to type 2 diabetes mellitus (T2DM) increases every year. We introduce and explore a new mathematical algorithm to evaluate wound-healing in foot ulcers associated to T2DM. Fifteen patients (nine women and six men), mean age of 70 ± 16 years were included. The evolution of their wounds followed-up for a period of 18-45 days. According to the Wagner grading system the ulcers were grade I (5 patients), grade II (9 patients), and grade III (1 patient). Clinically, the type of the ulcers was neuroischemic (12 patients) and neuropathic (3 patients). A new parameter is introduced, the "continuous linear healing rate" Dc that was more accurate with higher values and requires less quantifications than usual formulas to make a wound-healing projection.